Refining of petroleum hydrocarbons to produce gasoline



May 26, 1942. w. T. HANcock REFINING or' PETRLEUM HxjnRocARBNsuTo PRODUCE GAso LINE Filed Jan. 10, 1940 .NM mw Patented Mey 2e, 1942.

william' r. nancocarcn'g Beach, Calif.

Application January l0,

1940,` Serial No. .313,224

This invention relates to the cracking and relining of petroleum oils, and may be characterized generally as providing an improved system for initially subjecting a suitable charging stock to extensive cracking to produce a high percentage of lighter than gasoline but potential gasolineforming fractions and compounds, and then subjecting these cracked products to polymerization under conditions productive of an abnormally -high yield of recoverable gasoline fractions.

In accordance with the invention, the charging stock rst is subjected to cracking under high temperatures, and preferably' under relatively loW pressures, for-the purposeof causing a high degree of dissociation or cracking of heavier than gasoline fractions, and the production of lighter ythan gasolinecompounds capable of polymerization to form gasoline fractions of nondetoriating qualities.' Using the Ypresent system it is possible, because of the effectiveness ofthe polymerizing, stage, carbons 'to-.more intensive crackingthan would normally be desirable orveconomical due to excessive xed gas losses.

'After the hydrocarbons cracking under such conditions, the` cracked vapors are polymerized by contact with catalytic material and under high pressure that will produce an abnormallyV tion of the vapors in the presence of the catalyst. Following cracking, and with or without preliminary fractionation or polymerization, the vapors are mechanically compressed to a high pressure and preferably are subjected to polymerization by contacting them with adsorptive materiahas by passing the vapors through a body of ladsorptive clay. Being maintained under high pressure while subjected to the action of the clay, the nonvolatile constituents of the vapors undergo a high degree of polymerization, with resultant and proportionate formation `of gasoline fractions. After polymerization, the vapors may be further treated or fractionated by any suitable method to condense and separately remove fractions have been subjected toA to initially subject the hydrohigh degree of polymerizaheavier than gasoline, and to finally condense f the product gasoline.

The invention will be understood to best advantage from the following detailed description of a typical system embodying the invention and illustrated diagrammatically and in now sheet form in the accompanying drawing.

The charging stock introduced to the system through line I may consist of any suitable petroleum hydrocarbon or fraction thereof, capable kerosene distillate.

may. be necessary to crack the considerably high octane vrating compounds,will be formed.

Thus thecharging stock may consist of suitable crude oil or fractions such as fuel oil, gas oil or Also the invention contemplates cracking the hydrocarbons inistill II in either liquidor vapor phases, although in general it willbe preferred vto maintain cracking temperatures and pressures on a given hydrocarbon undergoing cracking, suchthat'thecracking reactions will occur at leastlargely in vapor phase. In flowing from line lli through the conventionally illustrated cracking still I I, which may be of any suitable type and design, the charging stock undergoes cracking at :temperatures 'that ymay range from 900A to 1300 F., or above, depending .upon the nature andcomposition of the charging stock, under however relatively low pressures, for

example from substantially atmospheric up to around lbs. per sq. in.v Where in order to obtainvthe desired degree `ofcracking. in still `Il it hydrocarbons at higher pressures, any desired pressure may be maintained on the oil undergoing cracking, as by a valve I2 in the outlet line I3, and. thepressure then reduced `tobelow -say 75 lbs. per sq. in., beyond the Valve. Y

The cracked hydrocarbons are discharged through line I3 into an enlarged separating chamber or reaction zone Iii wherein any carbon and unvaporized residue are separated from the vapors and removed from the system through line I5. The cracked vapors leaving chamber Iii through line I6 then are subjected to compression and subsequent polymerization, either with or without first being further treated in advance of the point of compression. As illustrative, the vapors may pass directly from line I6 through `Aline I'I to a compressor or series of compressors polymerization in fiowing upwardly tothe outlet "22 connecting with line I1. column 2!) may consist of an ordinary fractionatheavier ends are On the other hand,

ing column within which the condensed out of the vapors. The liquid polymers `or condensate, as the case may be, are removed recirculated through line 24 for cracking in still Il, or discharged tov storage through linev 25. Where column 20 or other similar apparatus is used, it is preferred to again subject theliquid polymers or condensate to cracking and to return the cracked products to chamber I4 inV order that from a given charging stock, a maximum yield of lighter cracked hydrocarbons will be produced for conversion in the high pressure stage of the system.

The relatively low pressure vapors owing through line l1 to the compressor, are compressed by the latter to a relatively high pressure, which ordinarily will be at least 200 pounds per sq. in.

higher than the vaporV pressure at the inlet side of the compressor, preferably to a pressure of around 400 lbs. to 600 lbs. per sq. gauge. Depending upon the characteristics of the cracked vapors and the type of catalyst employed in the polymerizing chamber, pressures in excess of those named may be used in order to obtain maximum degrees Vof polymerization. 'Ihe compressed vapors are discharged from com'- pressor I8 through line 26 to apolymerizing zone shown typically as a vertically extending i column 21. Prefera-bly, polymerization is at least 1n part induced by contacting the vapors with a suitablev adsorptive material such 'as vfullers earth, bauxite, Murock, or Deathv Valley clays, employed in sufncientlamount to subject the vapors to intimate and Yprolonged contact therewith. Accordingly, column 21A is shown to contain a body 28 of such adsorptive material extending vertically above thepoint of entry of the 1 vapors a considerable distance yso thatthe .va-

2 1y f 2,284,204 'from the base of column 20 through line 23 to be der high pressure, a large percentage of the higher boiling and normally uncondensible vapor fractions arel converted to condensible hydrocarbons within the gasoline range. At the same time, gum-forming compounds are converted to heavy liquid polymers which drain to the bottom of the column 21, from which they may be removed from the system through line 29 or recirculated throughline 30.V for recracking in still'A Il. Polymerized vapors leaving thev column through line 3| may be subjected to any desired further treatment and method of condensation or fractionation to produce the gasoline product. Merelyas illustrative, the vapors are shown to 4be subjected to initial fractionation in column 32, from the base of which heavy condensed fractions, for example within the gas oil range, 'may be removed to storage through lines 33 and 34, or recirculated to the cracking still through line 35. Leaving fractionating column 32, the vapors now -through line 36 to the fractionating column 31 wherein heavier than gasoline fractions, such as hydrocarbons within the kerosene distillate range, are condensed and removed -from the system through lines 38 and 39, or returned V'to 'the cracking still through line 40. The vah pors in fractionating column 32 may be subjected to reflux condensation rby condensate delivered Vto the top ofthe column from the base of fractionating column 31 through line: 1H.-4 Cracked gasoline vapors leaving column 31 through line pors have a prolonged path Aof flow through thek Y clay. One or more of'such columns of course.

may be employed, depending upon the desired time of ,contactV and length of vapor' travel through the clay. The polymerizing chamber may contain in place of or ,in addition .to the adsorptive clay, other catalytic agents vcapable of promoting polymerization of the vapors. For example the clay body may contain or be impreg- 1 1 -nated with` any of themetals,` metallic compounds, and particularly metallic salts,'known to `have the propertylof catalyzing the vreactions of polymerization. n j

In thus being subjected to polymerization unmers as will form at said low pressure,-then compressingthe vapors andA subjecting them to polyvmerization in contact Withyadsorptive material A at relativelyhigh pressure, separating from the vapors-those polymers Vforming,'atsaid high pressure, and nally subjecting the polymerized vapors to condensation to produce gasoline.AV

WmLfIAMT. HANCOCK. 

